000 AXNT20 KNHC 161115 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL ATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... 805 AM EDT MON APR 16 2012 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 8N13W TO 3N21W WHERE THE ITCZ AXIS CONTINUES S OF THE EQUATOR NEAR 27W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N TO S OF THE EQUATOR E OF 20W TO ACROSS THE PRIME MERIDIAN AND FROM 10N TO THE EQUATOR BETWEEN 47W-55W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF LINE FROM 4N27W TO 2N31W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE DOMINATES THE GULF N OF 24N ANCHORED JUST OFF NE FLORIDA AND EXTENDS OVER THE W ATLC. THIS UPPER RIDGE IS BEING AMPLIFIED N BY A STRONG UPPER TROUGH OVER THE CENTRAL PLAIN STATES. THIS UPPER TROUGH IS SUPPORTING A COLD FRONT STILL INLAND OVER TEXAS WITH A SURFACE TROUGH ALONG THE TEXAS COAST TO OVER NE MEXICO AND GENERATING SCATTERED TO HEAVY SHOWERS WITH SCATTERED TO NUMEROUS THUNDERSTORMS INLAND OVER TEXAS THROUGH N LOUISIANA TO ACROSS THE MIDDLE MISSISSIPPI VALLEY. THESE SHOWERS/THUNDERSTORMS ARE MOVING TO ALONG THE IMMEDIATE TEXAS COASTLINE. A SECOND UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS S MEXICO AND THE BAY OF CAMPECHE TO 25N93W. A SURFACE RIDGE ANCHORED IN THE W ATLC EXTENDS ALONG THE N GULF COAST TO SE LOUISIANA GIVING THE GULF SOUTHERLY RETURN FLOW N OF 25N. STRONG SUBSIDENCE AND DRY STABLE AIR DOMINATES MOST OF THE GULF WATERS. HOWEVER THE SOUTHERLY RETURN FLOW IS USHERING IN SOME LOW LEVEL MOISTURE AND SUBSEQUENT SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS N OF 28N TO INLAND OVER ALABAMA AND THE FLORIDA PANHANDLE BETWEEN 86W-89W LEAVING THE REMAINDER OF THE GULF WITH CLEAR SKIES THIS MORNING. PRESSURE GRADIENT BETWEEN COLD FRONT OVER TEXAS AND SURFACE RIDGE OVER W ATLC HAS FINALLY RELAXED AS RIDGE WEAKENS. THE COLD FRONT WILL BRIEFLY STALL OFF TEXAS COAST TUE THEN WEAKENS AND SHIFTS NE WED AND WED NIGHT. REMNANTS OF FRONT WILL DISSIPATE OVER N FLORIDA ON THU AS THE W ATLC SURFACE RIDGE BUILDS ACROSS COASTAL PLAINS. CARIBBEAN SEA... NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE ENTIRE CARIBBEAN. A RELATIVELY TIGHT PRESSURE GRADIENT COVERS THE CARIBBEAN AS THE SURFACE RIDGE OVER THE W ATLC EXTENDS S TO ACROSS THE GREATER ANTILLES TO OVER THE N CARIBBEAN N OF 18N AND IS GENERATING FRESH TO MODERATE EASTERLY TRADE WINDS ACROSS THE BASIN. MODERATE TO STRONG SUBSIDENCE AND DRY AIR ALOFT COVERS THE CARIBBEAN. A SHEAR AXIS EXTENDS FROM CENTRAL ATLC FRONT OVER DOMINICA ISLAND IN THE LESSER ANTILLES TO NEAR 13N73W. THIS SHEAR AXIS IS PROVING LIFT FOR SOME LOW LEVEL MOISTURE THAT REMAINS ACROSS THE CARIBBEAN TO GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90 NM N AND 60 NM S OF THE SHEAR AXIS. A SECOND BAND OF LOW LEVEL MOISTURE WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS EXTENDS WITHIN 60 NM OF A LINE FROM SW HAITI ALONG 17N80W TO 19N86W INCLUDING S JAMAICA. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH FAIR WEATHER THIS MORNING. THE SHEAR AXIS WILL CONTINUE TO WEAKEN AS IT MOVES E INTO THE TROPICAL ATLC N OF 16N THROUGH WED. ELSEWHERE W ATLC SURFACE RIDGE WILL MAINTAIN STEADY STRONG TO NEAR GALE NELY SURFACE FLOW ACROSS MOST OF BASIN TODAY THROUGH TUE. WINDS BEGIN DIMINISHING LATE TUE THROUGH THU. ATLANTIC OCEAN... A BROAD UPPER RIDGE IS ANCHORED JUST OFF NE FLORIDA COVERING THE W ATLC W OF 70W INTO THE GULF OF MEXICO. A SURFACE RIDGE DOMINATES THE W ATLC N OF 18N W OF 50W AND ANCHORED BY A 1028 MB HIGH JUST SW OF BERMUDA NEAR 31N66W. AN UPPER TROUGH REMAINS OVER THE CENTRAL ATLC N OF 20N BETWEEN 42W-70W SUPPORTING A COLD FRONT THAT EXTENDS FROM A 1007 MB LOW NEAR 33N48W ALONG 30N46W TO 20N52W WHERE IT DISSIPATES TO OVER DOMINICA ISLANDS IN THE LESSER ANTILLES BECOMING A SHEAR AXIS OVER THE CARIBBEAN WATERS. SCATTERED TO NUMEROUS SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 180 NM E OF THE FRONT N OF 26N WITH SCATTERED SHOWERS WITHIN 120 NM E OF THE FRONT BETWEEN 20N-26N AND ISOLATED SHOWERS WITHIN 75/90 NM EITHER SIDE OF THE REMAINDER OF THE FRONT. A LARGE UPPER RIDGE DOMINATES MUCH OF THE NE ATLC N OF 278N. A SMALL UPPER LOW IS JUST TO THE S CENTERED NEAR 24N22W EXTENDING AN UPPER TROUGH INTO THE TROPICS TO NEAR 8N17W AND GENERATING ISOLATED SHOWERS WITHIN 90/120 NM OF A LINE FROM THE CAPE VERDE ISLANDS TO THE COAST OF AFRICA NEAR 19N16W. A SURFACE RIDGE DOMINATES THE E ATLC N OF 17N E OF 43W ANCHORED BY A 1035 MB HIGH OVER THE AZORES. THIS IS LEAVING THE REMAINDER OF THE ATLC WITH FAIR WEATHER THIS MORNING. W ATLC SURFACE RIDGE WILL WEAKEN AS A COLD FRONT PASSES THROUGH THE NW WATERS S OF BERMUDA MON NIGHT AND TUE. THE RIDGE WILL SHIFT SLOWLY S ACROSS THE W ATLC WED THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW